This invention relates to diamond growth.
Various methods have been proposed and tried for growing diamond on diamond seed crystals by chemical vapour deposition (CVD) using gaseous carbon compounds such as hydrocarbons or carbon monoxide. A gaseous compound can be produced from a liquid carbon compound such as an alcohol or acetone. The gaseous carbon compounds may be decomposed by various methods including the use of heat and radio frequency (RF) energy, and also by means of microwave energy.
Examples of patents directed to methods of growing diamonds on substrates are U.S. Pat. Nos. 4,434,188 and 4,734,339 and European Patent Publications Nos. 288065, 327110, 305903 and 286306.
European Patent Publication No. 0348026 describes a method of growing crystalline diamond on a substrate which includes the steps of providing a surface of a suitable nitride, placing the substrate on the nitride surface, creating an atmosphere of a gaseous carbon compound around the substrate, bringing the temperature of the nitride surface and the substrate to at least 600.degree. C., and subjecting the gaseous carbon compound to microwave energy suitable to cause the compound to decompose and produce carbon which deposits on the substrate and forms crystalline diamond thereon. The nitride is typically silicon nitride and the frequency of the microwave is typically in the range 200 MHz to 90 GHz.